BuddyPress Group "Active" time does not change.

I have a group entitled "SEO". When I add an item (i.e. 'SEO tips') in the "What's new in SEO..." section, the "Active" time updates to the most recent time. When I wait an hour or so and then add a comment to my original 'SEO tips' post, the "Active" time does not update. Isn't adding a comment considered an "Active" part of the group?